1. Field of the Invention
The present invention relates generally to the removal of fuzz from articles of manufacture and more particularly to the removal of fuzz from envelopes used to enclose flexible, interchangeable computer memory disks without damaging the exterior surface of the envelope.
2. Description of the Prior Art
There are many instances wherein fibrous types of materials are used in products. For example, widely used in the computer industry is a data storage medium which consists of a circular disk of flexible material coated with magnetic particles. These disks are known in the trade as "floppy disks." Generally, the disk drive apparatus which is used to drive the disk and write data to and read data from floppy disks is designed so as to permit interchanging of disks. It is necessary to protect the recording surfaces of the disks from dust and other contaminants, both while the disk is installed in the disk drive apparatus and while the disks are stored when removed from that apparatus. The most widely known approach in the industry for protecting the floppy disks is by permanently sealing them into an envelope. The envelope has apertures adapted so that access may be had to the disk for coupling the disk drive to allow the disk to be driven and access by the transducer so that information may be recorded or reproduced while the disk is in the envelope. These envelopes normally have an aperture at their center which permits engagement of the circular disk with a drive spindle of the disk drive apparatus. A radially positioned oblong aperture in the envelope permits a magnetic transducer to interact with the disk to allow recording or reproducing of information thereon while the disk is rotated within the envelope by the drive spindle. Other apertures may be included, e.g. a circular aperture to permit an optical transducer to sense sectors of the disk.
The material used to construct these envelopes, as taught in U.S. Pat. Nos. 3,668,658, granted to Flores, et al., consists of two sheets or layers permanently bonded to each other. The outer sheet or layer is solid to provide mechanical protection for the recording disk. The inner layer, which is in intimate contact with the circular disk, consists of a sheet of porous, fibrous, low-friction, anti-static material whose properties permit the disk to rotate easily within the envelope and, in addition, clean the recording surfaces of dust, wear products and airborne contaminants. The process by which these envelopes are manufactured consists in first bonding continuous sheets of these two materials to each other and then mechanically punching the envelope apertures. Often the properties of the materials used to fabricate such envelopes are such that the outer solid layer has a lower melting temperature than the inner porous, low friction, anti-static layer. For example, frequently the outer layer is vinyl and the inner layer comprises bonded polyster fibres.
After the edges of an envelope have been cut and the apertures have been punched, "fuzz" from the inner, porous, low-friction, anti-static layer of envelope material remains around the edges of the sheet and of the apertures. The "fuzz" is in the form of small pieces of string-like material created along the edges of the sheets of material. This fuzz frequently results from the shearing, punching or cutting action. Excessive amounts of such fuzz in the completed assembly, consisting of the floppy disk sealed within its envelope, contaminate the drive mechanism and the transducer apparatus used to write data to and read data from the recording disk and interfere with its proper operation. Thus, it is necessary to minimize the amount of fuzz when producing and manufacturing the floppy disks.
Heretofore, the method employed to control the amount of fuzz present around the edges of the apertures of the envelopes consisted in keeping the punching tools sharp and discarding envelopes which had excessive amounts of fuzz. As a result, minimization of fuzz has been difficult and costly.
U.S. Pat. No. 2,967,326, granted to Collins, et al., teaches a method and apparatus for removing flash from the interior passages of articles molded under pressure in a two-part mold of material which is readily combustible and/or otherwise decomposible at elevated temperature. The method taught by Collins consists of exposing the article to a flow of hot gases and either protecting the interior surfaces of the passages with shields or, alternatively exposing them to a second flow of cooling gases immediately after the exposure to the flow of hot gases.